1. Field of the Invention
The invention relates to an apparatus for continuously processing foodstuffs under atmospheric pressure for the purpose of finishing (cooking or boiling) and/or dewatering them by contact with a heat carrier in the form of water, the apparatus comprising an installation having at least one separate preheating, boiling and recooling zone, each, of which zones includes a trough and, each being provided with chambers and traversed by means for conveying the treatment material, heat exchange means for transferring the thermal energy to be supplied to the heat carrier, means for supplying and removing the heat carrier and means for conveying the heat carrier within the installation.
2. Prior Art
Such apparatus is used in the industrial preparation of foodstuffs by heat treatment. Thus, they are e.g. used for finishing (boiling) all types of cooked sausage, vacuum-packaged sausage, collectively blister-packed sausage, takeaway meals in sealed plastic containers, fish products and the like products, or e.g. also for blanch all types of cabbage and bulbous or tubereous vegetables.
The temperature control is of decisive influence for the economical operation of such installations and is also of prominent importance with regard to maintaining the quality of the material to be treated. In order to avoid quality-reducing, punctiform overheating of the treatment material, efforts have been directed not only at precisely controlling the temperature, but also ensuring that the same temperature prevails throughout the water bath.
This processing is disadvantageous in many respects. Thus, in finishing processes it is, in most cases, desired to obtain as homogeneous as possible a temperature distribution in the product to be cooked, so that a temperature becomes effective on all parts of the cross-section which, at least, does not differ significantly from the temperature found to be favourable e.g. from the nutrition-physiological and sensory standpoints. However, particularly for economical reasons, a much higher temperature than the aforementioned one is normally used for the purpose of obtaining the desired core temperature more rapidly, i.e. to achieve a higher throughput due to shorter transit times, but this also leads to the material to be finished being overheated in its marginal regions before the core temperature has reached the desired value. Apart from the quality reduction mentioned in this context, this handling leads to a higher breaking or splitting rate, particularly in the case of sensitive packing casings, e.g. sausages with casings made from predetermined intestine qualities, during the heat treatment as a result of the increased stressing which consequently occurs in the material to be boiled. In addition, the energy balance is not good due to the heat losses which increase exponentially with the temperature.
An apparatus based on these ideas and perceptions is disclosed in FR-PS 2 569 533. This apparatus shows a tunnel-shaped structure and comprises a series of chambers separated from each other by doors, through which the material to be boiled, e.g. ham, which is in the boiling containers is conveyed by means of an intermittently driven trolley conveyor. The material to be boiled is first immersed in a hot bath, then it is left for a predetermined time without the supply of thermal energy for the purpose of temperature compensation between the marginal and the core temperatures, and finally it is slowly raised with respect to its temperature under moisture-chamber atmosphere during its passage through several treatment chambers, before it is recooled by immersion in low temperature water.
This known apparatus is provided as an architechtonic component of a production plant.
3. Objects of the Invention
It is an essential object of the invention to suggest a compact apparatus making it possible to subject foodstuffs to a continuous heat treatment using water as the heat carrier. It is another important object of the invention to ensure that the treatment takes place in an optimum manner taking account of the nutrition-physiologicaI and sensory demands. It is yet a further major object of the invention to enable that the process be performed automatically with a view to minimizing operating costs.